tips

Make and Mend tricks from Tim Anderson

Make and Mend tricks from Tim Anderson

When I was editing The Best of Instructables, one of my favorite authors in the book was Tim Anderson, who also edits our regular “Heirloom Technology” column in MAKE. Tim has hundreds of Instructables, many of them collections of time-saving, energy-saving, make-do, and kludgey-cool repair tips. Here are some excerpts from his Tips articles related […]

How-To: Restore the color of old Lego bricks

How-To: Restore the color of old Lego bricks

Turns out the yellowing of old ABS plastic is due to degradation of bromine-containing fire retardants which are added to the plastic during manufacture, which release elemental bromine, causing the yellow color. Shining UV light on the gel accelerates the decomposition of the fragile oxygen-oxygen bond in the peroxides it contains, generating reactive hydroxyl radicals which scavenge the free or loosely-bound bromine in the plastic that causes discoloration.